Pump control in sump applications is an important task in refining and chemical process plants. Although important, many of these pumping systems are not managed by the plant’s central control system and in most cases, there is little or no method in place for monitoring liquid level within the sump or the performance of the pumping system. The right control technology and implementation on sump applications has many positive economic outcomes such as overflow risk reduction, lower energy use and longer equipment life.

Sumps are part of a plant drainage system intended to collect fluids from process drains, oily water drains, fire water run-off and rain water drainage so that all the run off is controlled and treated appropriately so that environmental risk is eliminated.

process-drains-closed-system

Floats, bubblers, ultrasonic, and capacitive probes are common forms of level measurement for sump pump control, yet these technologies have proven maintenance intensive due to failures resulting from buildup, plugging, and foaming. Additionally, viscosity, process condition, and product variance can also cause inaccurate level measurements with these types of technologies.

The result of unreliable level measurement and pump control can be pump “Dry Run” condition or worse yet a sump overflow and possibly an  EPA reportable event. “Dry Run” conditions create costly problems such as excessive wear on a pumps bearings, seals and impeller. The best case scenario of “Dry Run” is early maintenance to repair or replace worn components. The need for complete replacement of the pump is also a possibility. One user noted a pump replacement cost of $80,000.00. An additional risk of an undetected “Dry Run” is pump failure when the pump is most critical and a sump overflow incident results.

So how do we solve this problem? Is there a better way to monitor liquid levels within the sump and protect the equipment?

One solution is an advanced pump control system that includes a pump control panel with a SIL qualified signal conditioning instrument for pump control and system performance monitoring and is integrated with SIL 2 microwave radar for continuous level detection and SIL 2 point level detection switch. Both transmitters can be mounted on one common flange, as small as 4″.

ps62_sw63-common-flg-sk5053

The pump control system should be customizable to meet specific application needs and the existing electrical system.

This type of packaged system can be specified and purchased for delivery pre-wired and ready for installation so that minimal field wiring is required. The simplified installation greatly reduces the field labor costs.

System components might include:

  • Continuous level measurement and/or point level safety switches
  • A Signal Conditioning Instrument with appropriate hazardous area ratings
  • Pressure sensors
  • Enclosure per application requirements
  • Selector switches, indicators, etc… as desired
  • All Electrical and dimensional drawings for approval & documentation

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Major benefits of this type of control system are:

  • Over-fill protection according to SIL 2
  • Dry Run protection according to SIL 2
  • FM Approvals for C1, D2 hazardous Areas
  • Lead-Lag pump switching to extend pump life
  • Reduced risk of an environmental incident
  • Increased life expectancy of rotating equipment via pump monitoring

Goat Nuggets thinks this is a pretty good solution for ensuring reliable sump control performance, yet we would love to hear from you in the comments section as to what others may be implementing?

 

 

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